Formation of twisted thread assemblies

ABSTRACT

Apparatus for forming a twisted-thread assembly comprising strand twisting means to impart to a strand alternating zones of opposite twist and strand convergence means adjacent the twisting means to converge the twisted strand with another strand to enable the strands to twist ply together thereby to form a twisted-thread assembly. A surface engages the strands after they leave the convergence means and in such a manner as to inhibit separation of the strands under ballooning forces generated by rotation of the strands as they twist ply together.

United States Patent Walls 1451 Feb. 27, 1973 [54] FORMATION OF TWISTED THREAD [56] References Cited ASSEMBLIES UNITED STATES PATENTS [75] Inventor: walls 3,225,533 12/1965 Henshaw ..57/34 Austra 3,434,275 3/1969 Backer et a1. ..57/34 AT [73] Assignee: Commonwealth Scientific and lndus- 3,443,370 5/ 1969 Walls ..57/34 trial Research Organization, Campbell, Australian Capitol Territory, Primary Exammer--Werner l-l. Schroeder Australia Att0rneySughrue, Rothwell, Mion, Zinn & Macpeak [21] Appl' 114316 Apparatus for forming a twisted-thread assembly comprising strand twisting means to impart to a strand al- [30] Foreign Application Priority Data temating zones of opposite twist and strand conver- A gence means adjacent the twisting means to converge Feb. 9, 1970 Australm ..PA 0281/70 the twisted Strand with another Strand to enable the strands to twist ply together thereby to form a twisted- [g%] (51 ..57/34 AS8317! thread assembly A surface engages the Strands after E g 774 106 they leave the convergence means and in such a manner as to inhibit separation of the strands under ballooning forces generated by rotation of the strands as they twist ply together.

5 Claims, 2 Drawing; Figures PATENIEU FEB2 7 191a BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the formation of twisted thread assemblies and is applicable particularly, but not exclusively, to the preparation of yarn comprised of staple fibers, for example wool fibers.

2. Description of Prior Art More specifically, the invention is concerned with the formation of twisted-thread assemblies by the process disclosed in our Australian Pat. No. 260,092. In this process the twisted-thread assembly is prepared by twisting a strand so that it has repeated along its length alternating zones of opposite twist and converging that twisted strand with another strand and allowing it to twist around that other strand. Both of the strands, or all of them if there be more than two, may be intermittently twisted and converged with the regions of twist in the strands suitably phased so that, when the strands commence to untwist, they twist around each other and this plying of the strands restrains the twist in each individual strand to result in self-stabilized plied assembly. Such an assembly will hereafter for the sake of convenience by called a self-twist thread or where applicable, a self-twist yarn.

Our Australian Pat. No. 288,664 discloses one particular form of apparatus for producing self-twist thread which apparatus comprises a strand twisting means in the form of a pair of oppositely rotated transversely reciprocating nip rollers. This apparatus is suited to simultaneous production of a plurality of selftwist threads and the present invention is particularly applicable to this form of apparatus.

When a pair of strands which have been individually twisted so as to have alternating zones of opposite twist are converged and allowed to twist ply together to form a self-twist thread, the individual strands, due to a ballooning effect, tend to-separate from one another at those regions where thethread has zero plying twist. It will be appreciated that in the production of alternating zones of opposite plying twist between the regions of zero twist, the regions of zero twist must rotate in order to form the twist in the zones between them. This rotation generates centrifugal forces which causes the individual strands to balloon out at the zero plying twist regions. This phenomenon, which becomes more marked with increasing strand speeds and increasing twist intensities can cause the lengths of the regions of zero plying twist to be increased and the twist intensity in the strands adjacent those regions to be decreased. The present invention overcomes this problem by providing a surface to engage the converged strands so as to inhibit the development of the ballooning phenomenon. Y r

In cases where a plurality of self-twist threads are being produced simultaneously the provision of antiballooning guide surfaces for all of the threads could lead to delays in threading up the apparatus. However the invention also provides a particularly convenient arrangement which ensures that each anti-ballooning guide can be correctly set very rapidly and with no threading up problems.

SUMMARY According to the invention there is provided apparatus for forming a twisted thread assembly, comprising strand twisting means to impart to a strand altemating zones of opposite twist and strand convergence means adjacent the twisting means to converge the twisted strand with another strand to enable the strands to twist ply together thereby to form a twisted thread assembly, characterized by the provision of a surface to engage the strands after they leave the convergence means and in such manner as to inhibit separation of the strands under ballooning forces generated by rotation of the strands as they twist ply together.

Said surface may be such as to engage the converged strands as they travel in a straight line path and over an extended part of that path. On the other hand, said surface may be a strand guide surface to guide the'converged strands through a change of direction.

More particularly the apparatus may comprise thread guide means to which the converged strands pass in a free span on leaving said strand guide surface and the strand guide is positionable such that it is offset from a direct line path between the convergence means and thethread guide means.

Preferably, the strand guide is movable out of engagement with the converged strands so that the converged strands then pass to said thread guide means in said direct line path but can be moved back so as firstly to engage the converged strands and then draw them out of said path. The strandguide may, for example, be formed as a recess in an edge of a swingable plate.

The invention further extends to a method of forming a twisted-thread assembly from at least two strands wherein a strand is twisted so that it has repeated along its length alternating zones of opposite twist and converging the twisted strand with another strand and allowing it to twist around that other strand thereby to form a twisted thread assembly and characterized by engaging the converged strands with a surface in such manner as to inhibit separation of the converged strands under the influence of ballooning forces generated by rotation of the strands as they twist ply together.

BRIEF DESCRIPTION OF DRAWINGS In order that the invention may be more fully explained, one particular embodiment thereof will now be described in some detail with reference to the accompanying drawings, in which:

FIG. I is a diagrammatic perspective view of a twisting apparatus embodying the present invention; and

FIG. 2 is a diagrammatic perspective view similar to FIG. 1 but showing the manner in which automatic threading of a number of anti-ballooning guides is achieved.

DESCRIPTION OF PREFERRED EMBODIMENT The illustrated apparatus is of the type that is fully described in our Australian Pat. No. 288,644. It comprises a pair of oscillating twisting rollers 3, 4 which are rubber covered and arranged so that they are just touching or with a small gap between them. These rollers are driven so that they reciprocate in opposite phase and rotate in opposite directions as indicated by arrows 5 to feed eight strands 6 through the nip. The rotary and reciprocatory drive means may be of a type fully described in Pat. No. 288,664 and is not shown in the present drawings.

As each of the strands 6 passes through the nip between the rollers it has imparted to it alternating zones of opposite twist, which zones are of equal length and are separated by twist changeover regions at which there is no twist. On leaving the nip the strands are grouped into four pairs by means of phasing guides 7 and convergence guides 8. The two strands of each pair are converged by the respective convergence guide 8 after one of the strands only passes around the respective phasing guide 7. On leaving convergence guides 8, the four pairs of converged strands pass around antiballooning guides 9 formed in the upper edge of a swingable plate 13. They then pass in free spans to four thread guides 10 which guide them to package winding apparatus.

The two strands of each pair are converged by the respective guide 8 with their alternating twist distributions suitably phased so that the tendency for the strands to untwist causes them to ply twist around one another to produce a ply-twisted yarn 11 having regions 12 of zero ply twist. The mechanism of self-twisting is fully described in the specification of Australian Pat. No. 260,092 and will not be explained in detail herein. Suffice to say that self-twisting can be achieved by converging the strands with their twist zones completely in phase, i.e., with the regions of zero strand twist coincident, or with their twist zones partly out of phase, i.e., with their regions of zero strand twist spaced from one another. The former conditions produce what is termed at in phase yarn whilst the latter conditions produce a phased yarn. However, in both cases the resultant yarn has alternating zones of opposite plying twist separated by regions of no plying twist.

, In the illustrated apparatus the phase relationship between the strand twist zones on convergence is controlled by the positioning of the phasing guides 7 relative to the convergence guides 8, and more particularly by the distance between them, which represents an increase in the path length which one of the strands must traverse before convergence relative to the other.

When anti-ballooning guides 9 are in their operative positions shown in FIG. 1, they cause a change in the direction of travel of the four pairs of converged strands, i.e., they hold the four strand pairs out of direct line paths to the thread guides 10. Thus the strand pairs firmly engage the anti-ballooning guides 9 in the region where self-twisting is occurring and this has the effect of inhibiting the ballooning phenomenon described above. In the absence of the guides 9, the rotation of the strand portions in the regions 12 would cause those portions to balloon out resulting in regions 12 being unduly long and the plying twist intensity adjacent those regions being diminished.

In the illustrated apparatus the anti-ballooning guides are adjacent the phasing guides 7 and are spaced approximately 94 inch from converging guides 8. The positioning of the anti-ballooning guides is not particularly critical but it is desirable that they be at least inch from the convergence guides.

It will be appreciated that if convergence guides 9 were fixed in their operative positions as shown in FIG. 1, they would add considerably to the time taken in threading up the apparatus. However, the guides 9 are formed in the edge of swinging plate 13 such that they can be automatically threaded during setting up. Plate 13 is mounted on a pair of hinges 14 so as to be swingable about a hinge axis 16 which is parallel with the axes of the rollers 3, 4. Thus it can be swung downwardly from the operative position shown in FIG. 1 and out of engagement with the four yarns 11. The four yarn guides 10 which deliver the yarns to the winding apparatus are positioned so that direct line paths to them from the convergence guides 8 are at an acute angle to planes perpendicular to the roller axes. The arrangement is such that as plate 13 is swung upwardly from its lowered position, guides 9 register with threads 11 when the upper edge of the plate reaches the threads. The guides 9 are formed at the roots of shallow V- notches so that the sides 17 of the notches serve as leading surfaces to accommodate any slight misalignment. As the plate continues to swing upwardly, guides 9 swing into their correct positions opposite phasing guides 7 as indicated by the arrows 18 in FIG. 1 and draw the yarns 11 out of direct line paths to the yarn guides.

In the illustrated construction the phasing guides 7 and the convergence guides 8 are threaded by hand with plate 13 lowered so that the anti-ballooning guides do not obstruct this threading step. The plate is then simply swung upwardly and the anti-ballooning guides are automatically threaded. This particular form of apparatus is therefore most convenient in operation. However this apparatus has been advanced by way of example only and the invention is in no way limited to its constructional details. Prevention of ballooning could be achieved by allowing the self-twist yarns to pass over a fixed surface so that their contact with this surface would prevent the ballooning effect. This surface could be extended in the direction of yarn travel to engage the yarns as they travel in straight line paths and over extended parts of those paths. The surface could be provided with grooves to receive and engage the yarns. In another arrangement tubular guides or open channel guides could engage the. yarns over straight lengths to prevent the ballooning effect. It is to be understood that such modifications can be made without departing from the scope of the appended claims.

I claim:

1. Apparatus for forming a twisted-thread assembly comprising strand twisting means for imparting alternating zones of opposite twist to a strand, strand convergence means adjacent said twisting means for converging the twisted strand with another strand to subsequently form a twisted thread assembly, thread guide means spaced from said strand convergence means to receive and guide the converged strand, strand guide means for engaging the converged strands intermediate said convergence means and said thread guide means, and support means for supporting said strand guide means for movement from an inoperative position spaced away from a direct line path between the convergence means and the thread guide means and through said direct line path to an operative position wherein the converged strands will be held out of said direct line path whereby upon moving said strand guide means from the inoperative to the operative position, the strand guide means will first engage the converged strands and subsequently draw them out of said direct line path to inhibit separation of the strands under ballooning forces generated by rotation of the strands as they twist ply together.

2. Apparatus for forming a twisted-thread assembly comprising strand twisting means for simultaneously imparting alternating zones of opposite twist to a plurality of strands, a plurality of convergence means adjacent said twisting means for converging each of the said plurality of strands with another strand to subsequently form a plurality of twisted thread assemblies, a plurality of thread guide means spaced from the plurality of convergence means to receive and guide the plurality of converged strands, a plurality of strand guide means for engaging the plurality of converged strand means intermediate said convergence means and said thread guide means, and support means for supporting said plurality of strand guide means for movement in unison between inoperative positions spaced away from direct line paths between the plurality of convergence means and the plurality of thread guide means and through said direct line paths to operative positions wherein the converged strands will be held out of said direct line paths whereby upon moving the strand guide means from the inoperative to the operative position the strand guide means will first engage the converged strands and draw them out of said direct line paths to inhibit separation of the strands under ballooning forces generate-d by the rotation of the strands as they twist-ply together.

3. Apparatus as claimed in claim 2 wherein said plurality of strand guide means is comprised of a plate having a plurality of recesses formed in one edge thereof and said support means includes means for pivotally mounting the opposite edge of said plate to provide for movement of said strand guide means.

4. Apparatus as claimed in claim 3 wherein said twisting means is comprised of a pair of cylindrical rollers forming a nip therebetween and roller drive means for rotating the rollers in mutually opposite directions and for reciprocating them longitudinally of their axes in opposite phase, a plurality of convergence means is comprised of a plurality of convergence guides spaced along a line adjacent said nip and parallel with the longitudinal axes of the roller, said plate being swingable about a hinge axis which is disposed parallel with said roller axes, and the thread guides means are positioned so that the direct line paths are at an acute angle to planes perpendicular to said roller axes.

5. Apparatus as claimed in claim 3 wherein said recesses are formed as shallow notches in the edge of said plate with deeper grooves located at the roots of said shallow notches, said notches serving to accommodate any misalignment of the converged strands and to guide them to said grooves when the plate is swung to move the strand guide means to their operative positions. 

1. Apparatus for forming a twisted-thread assembly comprising strand twisting means for imparting alternating zones of opposite twist to a strand, strand convergence means adjacent said twisting means for converging the twisted strand with another strand to subsequently form a twisted thread assembly, thread guide means spaced from said strand convergence means to receive and guide the converged strand, strand guide means for engaging the converged strands intermediate said convergence means and said thread guide means, and support means for supporting said strand guide means for movement from an inoperative position spaced away from a direct line path between the convergence means and the thread guide means and through said direct line path to an operative position wherein the converged strands will be held out of said direct line path whereby upon moving said strand guide means from the inoperative to the operative position, the strand guide means will first engage the converged strands and subsequently draw them out of said direct line path to inhibit separation of the strands under ballooning forces generated by rotation of the strands as they twist ply together.
 2. Apparatus for forming a twisted-thread assembly comprising strand twisting means for simultaneously imparting alternating zones of opposite twist to a plurality of strands, a plurality of convergence means adjacent said twisting means for converging each of the said plurality of strands with another strand to subsequently form a plurality of twisted thread assemblies, a plurality of thread guide means spaced from the plurality of convergence means to receive and guide the plurality of converged strands, a plurality of strand guide means for engaging the plurality of converged strand means intermediate said convergence means and said thread guide means, and support means for supporting said plurality of strand guide means for movement in unison between inoperative positions spaced away from direct line paths between the plurality of convergence means and the plurality of thread guide means and through said direct line paths to operative positions wherein the converged strands will be held out of said direct line paths whereby upon moving the strand guide means from the inoperative to the operative position the strand guide means will first engage the converged strands and draw them out of said direct line paths to inhibit separation of the strands under ballooning forces generated by the rotation of the strands as they twist-ply together.
 3. Apparatus as claimed in claim 2 wherein said plurality of strand guide means is comprised of a plate having a plurality of recesses formed in one edge thereof and said support means includes means for pivotally mounting the opposite edge of said plate to provide for movement of said strand guide means.
 4. Apparatus as claimed in claim 3 wherein said twisting means is comprised of a pair of cylindrical rollers forming a nip therebetween and roller drive means for rotating the rollers in mutually opposite directions and for reciprocating them longitudinally of their axes in opposite phase, a plurality of convergence means is comprised of a plurality of convergence guides spaced along a line adjacent said nip and parallel with the longitudinal axes of the roller, said plate being swingable about a hinge axis which is disposed parallel with said roller axes, and the thread guides means are positioned so that the direct line paths are at an acute angle to planes perpendicular to said roller axes.
 5. Apparatus as claimed in claim 3 wherein said recesses are formed as shallow notches in the edge of said plate with deeper grooves located at the roots of said shallow notches, said notches serving to accommodate any misalignment of the converged strands and to guide them to said grooves when the plate is swung to move the strand guide means to their operative positions. 